Artificial-limb lathe.



I. F. WIREBACK.

ARTIFICIAL LIMB LATHE.

APPLICATION FILED APR. I7. IQIT.

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ARTiFlCIAL LIMB LATHE APPLICATION FILED APR. H, I917.

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WITNESS J. F. WIREBACK.

ARTIFICIAL LIMB LATHE.

APPLICATION FlLED APR. 17. M17.

L$9L83f$ Patented Jan. M, 1919.

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6 a 7 23 Z5 mw w J %Lm WWNES INVENTOH. WW W, 1V 1cm llhll l ED STATES PATEN OFFICE.

JOSEPH F. WIREBACK, 0F PITTSBURGH, PENNSYLVANIA.

ARTIFICIAL-LIME LATHE.

To all whom it may concern:

Be it known that I, Josrrrr F. VVIREBACK, a citizen of the United States, and residing in the city of Pittsburgh, in the county of Allegheny, and State of Pennsylvania, have invention or discovered new and useful limprovements in Artificial-Limb Lathes, of which the following is a specification.

lily invention consists in certain new and useful improvements in turning lathes, and it is especially applicable to lathes used for hollowing out the wooden stump sockets of artificial limbs.

Generally speaking, my improved machine is characterized by a frame upon which are mounted parallel holders for the pattern and the wooden blank from which the socket is to be turned, means being provided for revolving said holders in fixed positions relative to the frame; a carriage slidably mounted on said frame in the plane of the axes of said holders, and a power-driven rotary member and a pattern engaging member mounted in parallelism on said carriage and capable of movement in unison transversely and pivotally of the same. Means are provided for moving said carriage along said frame toward said holdersby power, and in either direction along said frame by hand.

The pivotal movement of the cutter and pattern engaging member necessary to enable the cutter to move and cut in response to the irregularities of the pattern. However, as both the cutter and pattern engaging member swing from a common center located between their axes, the roller, which forms the pattern contact extremity of said member, does not remain in the same plane normal to the axis of the machine passing through the pivot point relative to the head of the cutter, but if sn-ung away from said axis, in response to the irregularitics of the pattern, said roller would lag behind and if swung toward said axis said roller would advance, relative to the cutter, thus preventing the faithful reproduction by the cutter in the inner wall of the socket of the exterior contour of the pattern.

To overcome this discrepancy, I so mount the pattern contact member that when its contact roller swings away from the axis of the machine, the latter is advanced in a degree su'fiicient to compensate for its tend eucy to retreat relative to the cutter head, and vice versa, when the roller is swung Specification of Letters Patent. Patented Jan. 14,, 1919 Application filed April 17, 1917.

Serial No. 162,599.

toward the axis of the machine, it is made to retreat to compensate for its tendency to advance relative to the cutter head, thus enabling said roller to maintain the same plane normal to the axis of the machine.

In the accompanying drawings, which are merely intended to illustrate the principles of my invention without limiting the scope of the same to the constructionshown, Fig ure 1 is a side elevationof my improved lathe; Fig. .Zis a top plan view of the same; Fig. 3 is a cross section taken along the line III-III in Fig. 2; Fig. 4- is a sectiontaken along the line IVlV in Fig. 2; Fig. 5 is a section taken along the line V-V in Fig. 2; F ig. 6 is a diagrammatic view of the geartrain by means of which the feed screw is operated in either direction; Fig. 7 is an end view of the machine, looking toward the right in Figs. 1 and 2, the end member of the machine frame being broken away and the carriage being partially in. section for the sake of clearness; Fig. 8 is a sectional view taken along the line VHIVIIT in Fig. 9; Fig. 9 is a face view on enlarged scale of the clutch nut, looking toward the left in Fig. 7 and showing the nut in its inoperative position disengaged from the screw, and Fig. 10 is a broken side elevation of the controlling bar of the pattern engagingroller, the slide bearings in which said bar moves being shown in vertical section.

The following is a detailed description of the drawings.

The frame of the machine comprises end members A and A, supported by vertical legs 1, and longitudinal and parallel guides B connectingsaid end members.

C is a carriage provided with depending lugs 2 having horizontal bearing holes through which the guides B extend, whereby the carriage is slidably mounted on the machine frame.

D is a feed screw parallel with the guides B and having its ends journaled in the end members A and A, one end of said shaft protruding from the member A.

3 1s a gear mounted on the protruding end of the shaft D. i

The carriage C is provided with a depending box through which said shaft D extends and whereon there is mounted a split clutch nut 5 controlled by the hand wheel 6 whereby said nut may be thrown into or out of mesh with said feed screw, thereby enabling the carriage to be moved along the guides B by the rotation of the feed screw. The clutch nut mechanism will later be more fully described.

E is a rack bar supported by the end members and engaged by a gear 7 which is mounted on a shaft 8 journaled in the bracket 9 depending from the carriage C, and provided with a hand crank 10 whereby said carriage may be moved by hand in either direction along the guides B when the clutch nut 5 is thrown into its inoperative position.

The top of the carriageC is of dove-tail cross section to receive the correspondingly recessed sliding base plate F which is thus capable of movement along said carriage transversely of the machine frame. 7

11 is a horizontal shaft rotatably mounted in a bracket 12 extending from the carriage C, while the other end of said shaft is threaded and engages a corresponding threaded hole in the bracket 13 extending from the sliding base plate F. The other end of said shaft is provided with a crank wheel '14 whereby said shaft may be turned to move said'base in either direction along the carriage.

15v is a circular bearing surface or plate on the base plate F upon which turns the pivotally mounted turn-table 16.

G is a platform rigidly mounted on the turn-table lG.

H is an electric motor centrally mounted on said platform.

17 is a bracket bearing mounted on one end of the platform G, and having journaled therein the horizontal cutter shaft l whose butt end protrudes and is provided with a belt pulley 18 which is connected by the belt 19 with the pulley 20 of the motor.

The other end of the cutter shaft 1 is provided with a detachably mounted cutter head 21. Thus the cutter head is rotatedby the motor.

At the other end of the platform G is rigidly attached an angular bracket 22 which extends forwardly parallel with the cutter shaft I.

J is a bar whose outer and preferably squared end is journaled in slide bearing 23 on the outer end'of'the bracket 22. 24: is a slide bearing on the base of said bracket 22 through which the butt of the bar J protrudes. To prevent rotary movement of said bar, the same is provided adjacent to its butt end with a rigidly attached fork or bifurcation 24 which is journaledin the slide bearing 24 parallel with the bearing 24.

To permit adjustment in the length of said bar J, it isv preferably made in two sections, the end of one section telescoping-into a cylindrical socket in the end-of the other section and secured rigidly in position,- as by means of a set screw 24.

Said bar may be straight or its outer portion may be offset, as shown in Fig. 2, away from the central axis of the machine, thus giving more clearance for adjusting the pattern roller to be described.

The butt end of the bar J protrudes from the bearing 2 1 and is in the form of a clevis, as shown in Fig.10, to receive a bolt 25 which passes through the are shaped slot of a segment 26 supported by a bracket 20 from the sliding base plate F.

It is perfectly evident that as the table (l turns on the base plate F, the bolt 25, which is attached to the bar J will slide in the slotted segment 26 and will interfere with the movement of the bar in unison with said table, and said bar will slide longitudinally in its bearing 23 and 24 moving outwardly along the bracket 22 or toward the right in Fig. 2 when the platform G turns counterclockwise and sliding in a reverse direction when the platform turns clockwise.

Adjacent to its outer end of the bar .l is provided with a transverse slot 27 in which is inserted the supporting arm 28 of the pattern engaging roller 29. The slot 27 and the arm 28 are preferablycurved substantially in the arc of a circle whose center is the axis of the platform G.

30 is a guide plate provided with a horizontal slot through which the arm 28 protrudes and which supports said arm and holds it in proper alinement against sagging or bending. Said plate is provided with a pair of legs 3O which extend through loops 30 on the under face of the bracket 22 and are secured rigidly in any adjusted position by means of set screws 30.

31 is a weight suspended by a cable 32 passing up over a pulley on the end of an arm 33 extending from the base plate F and attached to the end of an arm 34 mounted on the platform G adjacent to the butt end of the cutter shaft l. Thus the tendency is to swing the platform G clockwise and to resist a counter rotation of the platform.

The end member A of the machine frame is composed of a horizontal cross web 35, a vertical end flange 36 and a pair of vertical pedestals 37 rising at either end of the inner edge of the said web.

88 is a plate attached across the tops of the pedestals 37.

39 is a shaft journaled at one side of the machine on the plate 38 and the flange 2G. and protruding at its inner end. l ntermediate of its bearings, said shaft is provided with a gear 40. At its inner protruding end said shaft is provided with a pot chuck 41 provided with radial set screws 42 by means of which the wooden block K. from which the stump socket is to be hollowed out, is mounted in said chuck.

43 is a shaft at the other side of the machine journaled in bearings on the plate 38 and the flange 36 and having both its ends protruding. Between its bearings said shaft is provided with a pulley wheel 44 and a gear 45 alined with the gear 40. The pulley 4A is connected by means of a belt 4C6 with a source of rotary power, not shown.

47 is an idler gear, mounted on a spur shaft 48- journaled on the plate 38 and intermeshing with the gears 40 and L5. The gears 40 and 45 are of the same diameter so that they rotate at the same speed.

The inner protruding end of the shaft 43 is provided with a chuck 49 in which may be secured, as by means of set screw 50, the end of a shaft 51 on which is rigidly mount; ed or formed the cast L of the stump, which acts as a pattern, and which when the machine is in operation is perimetally engaged by the contact roller 29.

The other end of the shaft 51 is journaled in a bearing 52 carried by a triangular support M which is slidably mounted on the guides B. Thus the block K and the pattern L are supported in parallelism and rotated together in the same direction.

I will now proceed to describe the method provided for rotating the screw shaft D in either direction, so as to advance the can riage C toward or retreat it from the end A of the machine.

On the outer protruding end of the shaft 43 is fixed a gear 53. 54C 2111C 55 are parallel gears journaled to move in unison 011 a spur shaft 56 extending from the flange 36 of the end A.

The outer gear 55 is in mesh with a gear 57 journaled on the spur shaft 58 also extending from the end A. The gear 57 is also in mesh with the gear 3 on the screw shaft D. I

59 is a frame pivotally supported on the shaft 56 and carrying the twin intermeshing gears 60 and 61. When the frame 59 is swun into one position, shown in Fig. 7, the gear 60 meshes with the driven gear 53 and the gear 61 meshes with the gear 54, thus advancing the carriage C toward the end A. When the frame is swung into its other position, the gear 61 meshes with the driven gear 53, while the gear 60 meshes with the ear 54., thus rotating the shaft D in the opposite direction, and causing the carriage C to move toward the end A. The position of the frame is adjusted by means of a handle 62 provided with a spring latch 63 which is adapted to engage one of a pair of holes in the flange 36 and hold the frame stationary.

The following is a detailed description of the clutch nut structure shown in the drawings and found to be a satisfactory device in practice.

64 is a box carried by and preferably cast integral with the carriage C. The back of said box is closed by a removable lid 65,

through which extends the shaft 66 on which the hand wheel 6 is mounted.

67 is a disk rigidly mounted on the inner end of the shaft 66 within the box 641-. The front face of the disk 67 is provided with a pair of studs 68 in the same diametrie line and equally distant from the center of the is I.

Said studs engage eccentric are shaped slots 69 in the faces of a pair of slides 70 which are capable of vertical movement in opposite directions in the front part of the box 64. Said slides 70 are provided with pins 71 which extend through a vertical slot 72 in the front wall of said box and engage snugly fitting holes in the rear faces of the nut blocks or halves 5 whose rear faces are provided with vertical edge flanges 73 which engage and travel in the undercut vertical guides 74 on the front of the box 64. It is thus seen that by means of the hand wheel 6, the carriage C may be operatively connected with the screw D or released therefrom at will.

The operation of my improved lathe is as follows,

The shaft 51 with the pattern L mounted thereon is mounted in the machine, one end of the shaft being fixed in the chuck 49 while its other end is journaled in the bearing 62 of the support M which is moved along the guides B into the proper position.

The Wooden block K from which the socket is to be hollowed out is then clamped into the pot chuck 4.1. It is preferable to first bore the axis of the block to prevent the binding of the cutter head.

The carriage C with the mechanism mounted thereon is then moved by means of the hand crank 10 along the guides B until the roller 29 comes into contact with the perimeter of the pattern L on the outer side of the latter and the cutter 21 impinges against the end of the block K. The arm 28 of the roller 29 is adjusted in. the slot 27 to permit the cutter to cut around a relatively small core for the first cut to facilitate the removal of the wood.

Where the roller 29 comes into contact with a marked angular depression in the surface of the pattern L, unless a shifting of the cutter shaft I were possible, the cutter head could not out beyond the sharp projection on the inner wall of the socket as said projection would hold the cutter shaft I away from its proper position. This would furthermore strain the cutter shaft and the guide rod J out of parallelism. To avoid this difficulty, I shift the sliding base plate F on the carriage C so as to change the angle in which the cutter shaft I may turn and the bar J operate to throw the cutter head to cut into the wood behind such a projection.

The roller 29 is kept in continuous contact with the surface of the pattern L as the latter revolves by theinfluence. of the weight 31.

The gear train is adjusted to rotate the screw D to advance the carriage C toward the end of A of the machine; the clutch nut 5 is thrown into its operative position and the motor H started to rotate the cutter 21. Thus as the lathe continues to operate the cutter head 21 advances and cuts out a relatively small bore in the revolving block K leaving an interior wall corresponding in contour to the exterior contour of the pattern L but of less diameter.

When the roller 29 has traversed the full length of the revgolving pattern L the clutch nut 5 is thrown off and the carriage C run back by hand crank 10 until the cutter head 21 is again at the front end of the block K. The arm 29 is now lengthened in the slot 27 to swing the cutter head farther away from the axis of the proposed socket and the above described operation is repeated. Thus a somewhat larger bore of the proper wall contour is hollowed out of the block K.

By making repeated cutting of progressively greater diameter the wood is removed from the interior of the socket without binding, until a socket with a bore of the proper size is obtained.

The purpose of making the length of the bar J adjustable is that the roller 29 may at all times occupy the same plane relative to the cutter head 21 normal to the axis of the machine. Thus if a shorter cutter head he used, the bar J should be shorter than when a longer cutter head is used, since the length of the cutter shaft and head would thereby be lessened or increased.

The advantages of my improved machine are manifold and self-evident. Among them may be mentionel the following.

The compensatory sliding movement of the bar J, under the control of the segment 26, maintains the roller 29 in a constant plane normal to the axis of the machine, the curve of the slot in the segment being such that the sliding movement of said bar J is sufficient for this purpose. Thus the cutter head and contact roller advance in unison andthe reproduction of the exterior wall of the pattern in the interior wall of the. socket is uniform and accurate.

The pivotal and transverse sliding movements of the common mounting of the cutter head and contact roller insures prompt and accurate response of the cutter to the shifting of the roller in its contact with the pattern. It is also possible to obtain this very desirable accuracy of reproduction where the contour of the pattern is very irregular, requiring hollows to be cut out in the socket beyond inwardly extending projections of the wall of the socket.

The machine is much simpler in construction than the prior machine used in the art, and is therefore cheaper to build and much more durable. Its accuracy in turning out work has been proved by long continued and very extensive use.

What I desire to claim is 1. In a lathe, the combination of a supporting frame, means for mounting and rotating a pattern and a blank in parallel positions on said fame, a rotary cutter and a pattern engaging member pivotally mounted in unison on said frame, means for causing a relative movement between the pat tern and the pattern engaging member and between the blank and the cutter respectively and means for causing a relative movement between the contact end of the pattern engaging member and the head of the cutter to maintain the head of said cutter and the contact end of said pattern engaging member in the same relative positions normal to the axis of the frame during the pivotal movement of said cutter and member.

2. In a lathe, the combination of a supporting frame, means for mounting and rotating a pattern and a blank in fixed parallel positions longitudinally of said frame, a carriage mounted to slide longitudinally of said frame, a platform horizontally pivoted on said carriage and capable of adjustment thereon in a plane normal to the path of movement of the carriage, a rotary cutter and a pattern contact member mounted in parallel on said platform, and means for maintaining the pattern engaging portion of said member in a constant plane normal to the longitudinal axis of said frame relative to the head of said cutter as said platform turns on said carriage, substantially as and for the purposes described.

3. In a lathe, the combination of a supporting frame, means for mounting and retating a pattern and a blank in fixed parallel positions longitudinally of said frame, a carriage mounted to slide longitudinally of said frame, a rotary cutter and a pattern engaging member pivotally mounted in uni. son on said carriage. and means for moving said pattern engaging member longitudinally as it swings whereby its contact end is maintained in a constant plane normal to the longitudinal axis of said frame relative to the head of said cutter. substantially as and for the purposes described.

4. In a lathe, the combination of a supporting frame, means for mounting and rotating a pattern and a blank in fixed par allel positions longitudinally of said frame, a carriage mounted to slide longitudinally of said frame, a platform pivotally mounted on said carriage and adjustable thereon, a rotary cutter and a pattern engaging member mounted in parallel on said platform. and means for moving said pattern engaging member longitudinally as it swings with said platform vvhereby its contact end is maintained in a constant plane normal to the longitudinal axis of said frame relative to the head of said cutter. substz'mtially as and for the purposes described.

5. In a lathe, the combination. of a supporting frame, means for mounting and rotating a pattern and a blank in fixed. par allel positions longitudinal of said frame. a carriage mounted to slide longitudinally of said frame, a rotary cutter and a guide bar pivotally mounted in unison on said carriage, a horizontally arranged curved contact member adjustably mounted on the end of said bar, and means whereby said bar moved longitudinally as it swings whereby the point of contact of said member With the pattern is maintained. in a constant plane normal to the axis of said frame relative to the head of the cutter. substantially as and for the purposes described.

6. In a lathe. the combination. of a sup porting frame, means for mounting and rotatingr a pattern and a blank in fixed parallel positions longitudinally of said frame, a carriage mounted to slide longitudinally of said frame, a platform pivotally mounted on said carriage, a rotary cutter and a pattern contact member mounted in parallel on. said platform, and means for maintaining the pattern engaging portion of said memher in a constant plane normal to the lOIlQZitudinal axis of said frame relative to the head of said cutter as said platform turns on said carriage, substantially as and for the purpose described. '7'. lln a lathe. the combination of a supporting frame. means for mounting: and rotating a pattern and a blank in fixed parallel positions lone'itudinally of said frame, a carriage mounted to slide longitudinally of said frame. a platform pivotally mounted on said carriage. rotary cutter and a pattern contact member mounted in parallel on said platform. and means for slidablv adjusting the pattern contact member longitudinally of the platform as the latter swings whereby its contact end is maintained in a constant plane normal to the longitudinal axis of said frame relative to the head. of said cutter. substantially as and for the purpose described.

P. ln. a. lathe. the combination of a. supporting" frame, means for mounting and rotating a pattern and a blank in fixed parallel positions longitudinally of said frame. a carriage -mounted to slide longitudinally of said frame. a rotary cutter and a pattern engaging" member pivotally mounted in unison on said carriage, and means for adyancin or retracting said pattern engaging member longitudinally according to its pivotal movements whereby its contact end is maintained in a constant plane normal to the longitudinal axis of said frame relative to the head of said cutter, substantially as and for the purpose described.

9. ln a lathe, the combination of a supporting frame, means for mounting and ro tatinp, a pattern and a blank in fixed parallel positions longitudinally of said frame, a carriage mounted to slide longitudinally of said frame, a rotary cutter and a pattern engaging member pivotally mounted in unison on said carriage, and means for main taining' the contact end of the pattern engaging member and the head of said cutter in a constant plane normal to the longitudinal axis of said frame during their pivota movements.

10. In a lathe, the combination of a sup porting" frame, means for rotating a pattern and blank in parallel on said frame. a rotary cutter and a pattern contact member pivotally mounted in unison on said frame, means for causing a relative lengthwise movement between the pattern and the pattern contact member and between the blank and the cutter respectively, and means for maintaining" the contact end of the pattern engaging" member and the head of said. outter in the same relative positions normal to the axis of the frame during the pivotal movement of said cutter and member.

11. In a lathe, the combination of a supporting frame, means for mounting and rotating a pattern and a blank in parallelism and longitudinally on said frame. a carriage mounted to slide longitudinally on said frame. a cutter and a pattern contact member pivotally mounted. in parallelism on said carriage and means for maintaining" the contact end of the pattern engaging" member and the head of the cutter in the same relative positions normal to the axis of the frame during" the pivotal movement of said cutter and member.

12. In a lathe. the combination of a supporting frame, means for rotating, a pattern and a blank in parallel on said frame. a rotary cutter and a pattern contact member pivotally mounted in. unison on said frame. means whereby the pattern engaging portion of said member is caused to traverse the pattern longitudinally as said pattern is reyolyed. and means for maintaining" the pattern engagingportion of the pattern contact member in a constant plane relative to said cutter and normal to the arris of the machine.

Signed at Pittsburgh. Pa, this 18th day of April, 1917'.

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denies of this patent may be obtained for five cents each, by addressing; the tlomm'leuloncr of Patents. Washington, ne 

